python基础----Day06习题

列表的嵌套练习⭐⭐⭐

list_data = [[11, 12], [21, 22, 23], [31, 32, 33, 34]]

一.通过下标

需求一:实现列表嵌套的遍历

list_data = [[11, 12], [21, 22, 23], [31, 32, 33, 34]]
for i in range(len(list_data)): #标出大整体下标
    for j in range(len(list_data[i])) #标出小整体下标
        print(f'list_date{[i]}{[j]} = {list_data[i][j]}') #输出
    print('-'*30)

运行得到:

需求二:对每个小整体求和

list_data = [[11, 12], [21, 22, 23], [31, 32, 33, 34]]
for i in range(len(list_data)):
    group_sum = 0
    for j in range(len(list_data[i])):
        value = list_data[i][j]
        group_sum += value
    print(group_sum)
        

需求三:求出整个列表的和

list_data = [[11, 12], [21, 22, 23], [31, 32, 33, 34]]
sum = 0
for i in range(len(list_data)):
    group_sum = 0
    for j in range(len(list_data[i])):
        value = list_data[i][j]
        group_sum += value
    sum += group_sum
print(sum) #注意for循环的作用域

二.直接取值

列表数据直接遍历,依次取出即可

list_data = [[11, 12], [21, 22, 23], [31, 32, 33, 34]]
sum = 0
for group in list_data:
    group_sum = 0
    for value in group:
        group_sum += value
    sum += group_sum
    print(group_sum)
print(sum)

熟能生巧,自己动手试试吧